Dry-shaving apparatus



Nov. 16, 1943. DE GRQQT 2,334,254

DRY SHAVING APPARATUS Filed Feb. 26, 1941 J Q21 cie 6900 2 Patented'Nov. 1943'v 2,334,254 DRY-SHAVING APPARATUS Jan de Groot, Eindhoven, Netherlands; vested in the Alien Property Custodian Application February 26, 1941, Serial No. 380,736 In the Netherlands January 20, 1940 4 Claims.

This invention relates to dry-shaving apparatus of the type comprising a cutting plate and a cutter movable at the back thereof usually by means of a rotatable shaft. The cutting plate which is applied against the .skin has usually a comparatively small surface suitably apertured for example by means of slits which extend to' the outer edge of the cutting plate. In practice it has been found that in such apparatus-in which the hair-cutting part of the cutting plate is essentially circularthe surface of the cutting plate which makes contact with the skin and which in all directions has comparatively small dimensions compared with apparatus comprising a rectangular cutting plate and a cutter reciprocating at the back thereof, is frequently placed slightly inclined to the skin so that proper shaving is impossible. This will receive further consideration in the following description of the figure which is given for the purpose of a more detailed explanation.

A further difficulty, particularly if the cut ting plate is rigidly pressed against the skin so as to cut the hairs as short as possible, is that the slits extending into the edge of the cutting plate may irritate the skin.

Moreover, the cutting plate is susceptible to injury at the edge near the debouchment of the slits and the replacement of the cutting plate entails considerable cost because of its costly construction.

According to the invention, these difficulties encountered in the above-mentioned apparatus are obviated by a preferably continuous protective edge which bulges the skin and is arranged at a short distance from the edge of the cutting plate for the purpose of obtaining an appreciable increase of the supporting surface by which the cutting plate bears on the skin. The appreciable increase of the part of the cutting head that engages the skin results in that the active part of the cutting plate is practically prevented from being placed so as to be inclined to the skin and the apparatus according to the invention thus permits quicker and better shaving even by unskilled users.

The measure according to the invention also permits the cutting plate to be constructed thinner than hitherto and in the case of the present apparatus the cutting plate may be as thin as admissible from a mechanical viewpoint, for example from 0.04 to 0.05 mm. In principle, shorter cutting of the hairs is thus facilitated.

Due to the protective ring irritation of the skin isavoided, even in the case of firm engagement of the cutting plate with the skin, and

the outer edge of the cutting plate which is very liable to mechanical damage is uniformly protected on all sides.

A further advantage of the cutting head according to the invention is that owing to the bulging out of the skin between the protective edge and the outer edge of the cutting plate the hairs are erected, are exposed to a greater extent and can consequently be cut off shorter. Moreover, a shorter shaving time is thus obtained; The use of the protective edge permits the cutting head to be moved more readily over the skin than in the case in which a protective edge is not provided and in which only the cutting plate having slits formed in it exists.

It has been found particularly suitable to arrange the protective edge at a distance'of at least half a millimetre, preferably of from 1 to 2 mms., from the outer edge of the cutting plate. Generally, however, this depends on the nature of the outer edge of the cutting plate (sharp or more or less rounded) on the arrangement of the protective edge above, flush with or below the plane of the cutting plate and on the thickness and also on the nature of the protective edge itself (more or less sharp or greatly rounded).

The cutting plate is preferably circular and the edge is constituted by a smooth ring rounded on the side to be applied against the skin and this facilitates moving over the skin.

For the purpose of simple mass production and proper engagement of the skin it is preferable that the protective edge should be located in a plane.

It has been found that while conserving substantially the same shaving time the use of the protective edge permits of omitting the debouchments of the slits at-the outer edge of the cutting plate which are enlarged to have a funnelshape so that the width of these debouchments may be equal to the width of the slits. Manufacture of the cutting plates is thus cheaper and simpler. I

The thickness of the protective edge at the level of cutting plate is preferably about from 1 to 3 mms.

In forms of construction in which apertures in the central part of the cutting plate extend into a depression it may be advantageous to shape the part of the cutting plate adjoining these debouchments in the form of a slit. This may be effected, for example, by the provision of a raised part or of an annular edge at the centre of the cutting plate. Similarly to the abovedescribed outer edge, this protuberance or edge inter alia ensures the advantages of improved erection of the hairs by bulging out of the skin and of less irritation.

In order that the invention may be clearly understood and readily carried into eflect one form of construction of the cutting head according to the invention will now be described more fully with reference to the accompanying drawing. in which Figs. 1 and 2 are a plan and a cross-sectioned view of a part of a dry-shaving appliance diagrammatically shown.

The cutting head comprises a cutting plate I having a diameter of 15 mms. and being provided with radial slits 2 extending into the edge 3 of the cutting plate and into a central depres-,

sion 4 and a cutter arranged at the back of the cutting plate end provided with three legs 8 having cutting edges 1. The cutter is driven, for example from an electric motor, by means of a shaft (not shown) comprising extensions that enter into apertures 8 of the cutter which thus rotates or reciprocates about the shaft. Since the cutter consequently performs a rotation or partial rotation at any time the active part of the cutting plate where the hairs are cut off is circular. As for the sake of simplicity it is preferable that the circumference of the cutting plate into which the slits extend does not diverge too much from the circular shape of the active part so that in principle the outer circumference of the cutting plate will therefore generally exhibit a more or less regular figure around the said circular form and it is self-evident that the edge of thecutting plate which encloses the active part should not extend therefrom too far, the supporting surface of the cutting plate, which is to be applied against the skin and therefore has comparatively small dimensions in any direction, is small in principle. Also for other reasons (cheaper production, saving in material and motor capacity) the diameter of the cutting plate will preferably be given a minimum value e. g. from 15 to 20 ms. with the result, however, that in practice the drawback is experienced that a great many users of such apparatus will place the cutting head so as to be inclined to the skin and not in the full contact therewith. This results r either in failure to shave or in defective and prolonged shaving. In contradistinction to this, with vdry-shaving apparatus having a cutting plate of elongated, rectangular form and having formed in it a number of parallel slits across the longitudinal axis proper engagement of the skin is directly obtained by reason of the considerable length of the cutting plate, as in the case of an ordinary safety razor, so that the measure according to the invention for increasing the supporting surface engaging the skin is not generally needed with such devices.

According to the invention, for the purpose of increasing the surface of the cutting plate that bears on the skin. the circumference of the cutting plate I, which in the figure is assumed to be circular, is surrounded at a short distance by a ring 9 which has a smooth and preferably uninterrupted and rounded edge Ill which is located in a plane at about the level of the supporting 7 as to have a fixed or an adjustable height, the,

user being thus enabled in the latter case to regulate the height of the edge ill at will. This: may be eflected for example, by varying the de-' gree of threading between the nut II and the casing I! in which case for holding the cutting plate I the gasket l3 interposed between adjacent surfaces of the nut and the cutting plate is made of appropriate thickness or consists of a compressible material.

What I claim is:

1. A dry-shaving device comprising a cutting plate having a plurality of apertures extending to the edges thereof, a movable cutter member engaging the inner surface of said plate, means to bring the surface to be shaved into good shaving relationship with the outer surface of said cutting plate, said means comprising a member having a protective edge spaced from the outer edge of the cutting plate and projecting beyond all portions of the outer surface of the cutting plate.

2. A dry-shaving device comprising a circular cutting plate having a plurality of apertures extending to the edges thereof, a movable cutter member engaging the inner surface of said cutting plate, means to bring the surface to be shaved into good shaving relationship with the outer surface of said cutting plate, said means comprising a member having a circular protective edge spaced from and surrounding the edge of the cutting plate and projecting beyond all portions of the outer surface of the cutting plate.

3. A dry-shaving device comprising a cutting plate having a plurality of apertures extending to the edges thereof, a movable cutter member engaging the inner surface of said cutting plate, means to bring the surface to be shaved into good shaving relationship with the outer surface of said cutting plate, said means comprising a member having a continuous protective edge spaced from the outer edge of the cutting plate and projecting beyond all portions of the outer surface of the cutting plate, and means to adjust the extent to which the protective edge projects beyond said outer surface.

4. A dry-shaving device comprising a casing, a circular cutting plate having a plurality of apertures radially extending to the edges of the cutting plate, a movable cutter member disposed within said casing and engaging the inner surface of the cutting plate, a ring member surrounding the cutting plate and securing the same to the casing, said ring member having a circular protective edge spacedly surrounding the edge of the cutting plate and extending beyond all portions of the outer surface of the cuttingplate.

JAN n: enoo'r. 

